About this replacement
Panasonic KX-TD7690 — 3.7V Li-Polymer Replacement Battery (N4HUGLB00001)
This 3.7V 650mAh Li-Polymer battery replaces the original pack in the Panasonic KX-TD7690 DECT cordless phone handset. It fits the KX-TD7690 directly and matches the OEM connector and form factor. Capacity is 650mAh (2.41Wh), identical to the factory specification.
- KX-TD7690 handset fit: The KX-TD7690 uses a slim Li-Polymer cell at 3.7V nominal. This pack shares the same voltage rail, physical dimensions (51.40 × 21.90 × 5.90mm), and connector orientation as the original, so the handset BMS accepts it without renegotiation.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a KX-TD7690 handset. The BMS accepted the pack immediately, charge current ramped normally from the base station, and the handset reached full charge indication without error flags.
- First-charge protocol for Li-Polymer cordless packs: After fitting, seat the handset in the base and leave it on charge for a full 16 hours before first use. Li-Polymer cells shipped in storage state need a complete slow charge to calibrate the fuel gauge and reach rated capacity from cycle one.
Talk time shorter than original battery after replacement
A freshly installed Li-Polymer pack often delivers less talk time than expected for the first two to three cycles. The cell ships partially discharged and the handset's fuel gauge hasn't yet calibrated to the new pack's actual capacity. Run two or three full charge-to-depletion cycles through normal use and the reported and actual capacity will align. After cycle three, talk time should match the 650mAh rating.
Handset not pairing with base after battery swap
Removing the battery on some DECT handsets clears the pairing register stored in volatile memory. The KX-TD7690 may show "searching" or refuse to connect after a battery swap. To re-pair, hold the handset's registration button until the base unit confirms pairing — the exact sequence is in the KX-TD7690 system guide under "Handset Registration." Once re-paired and fully charged, the handset operates normally.